Vitoux Laura, Guignard Marie, Penin Nicolas, Carlier Dany, Darriet Jacques, Delmas Claude
CNRS, Université de Bordeaux, Bordeaux INP, ICMCB UMR 5026, 33600 Pessac, France.
Inorg Chem. 2020 Mar 16;59(6):4015-4023. doi: 10.1021/acs.inorgchem.9b03688. Epub 2020 Mar 1.
NaMoO was synthesized as a layered oxide from the reaction between the layered oxide NaMoO and metal sodium. Its structure was determined from high-resolution powder X-ray diffraction, and it can be described as an α-NaFeO distorted structure in which sodium ions and molybdenum atoms occupy octahedral interstitial sites. Chains of "diamond-like" clusters of molybdenum were evidenced in the [MoO] layers resulting from the Peierls distortion expected in a two-dimensional triangular lattice formed by transition metal atoms with a d electronic configuration. Molybdenum-molybdenum distances as short as 2.58 Å were found in these clusters. The magnetic moment recorded at low temperatures and at room temperature showed that NaMoO presents a very low magnetic susceptibility compatible with the localization of the 4d electrons in the Mo-Mo bonds. This localization was confirmed by DFT calculation that showed the NaMoO was diamagnetic at 0 K. A sodium battery was built using NaMoO as the positive electrode material, and we found that sodium ions can be reversibly deintercalated and intercalated in NaMoO, indicating that this compound is one of the many phases existing in the NaMoO system.
钼酸钠（NaMoO）是由层状氧化物NaMoO与金属钠反应合成的层状氧化物。其结构由高分辨率粉末X射线衍射确定，可描述为一种α-NaFeO扭曲结构，其中钠离子和钼原子占据八面体间隙位置。在由具有d电子构型的过渡金属原子形成的二维三角晶格中，由于预期的佩尔斯畸变，在[MoO]层中发现了钼的“类金刚石”簇链。在这些簇中发现钼-钼距离短至2.58 Å。在低温和室温下记录的磁矩表明，NaMoO具有非常低的磁化率，这与4d电子在Mo-Mo键中的局域化相一致。密度泛函理论计算证实了这种局域化，结果表明NaMoO在0 K时是抗磁性的。以NaMoO作为正极材料构建了钠电池，我们发现钠离子可以在NaMoO中可逆地脱嵌和嵌入，这表明该化合物是NaMoO体系中存在的众多相之一。
